This exhibit is a photomultiplier that was once part of a piece of medical X-Ray apparatus.
The dynodes are under the paper label. The circuit board is integrel to the tube and looks like the pre-amplifier.
The paper label carries this information but no details can be found.
Another circuit board is held within the vacuum envelope.
The entry window and photo-cathode.
Here the tube is seen in the form of an X-Ray image.
The wide glass tube envelope is 60 mm in diameter, and excluding the base pins is 215 mm tall.
Updated July 21, 2014.